1. Field of the Invention
The present invention relates to sawing machines and has specific reference to a machine for sawing commercial products in the form of plates consisting of metal, wood, chipboard or other similar materials.
Various products of metal, wood, chipboard or other similar materials require, at the end of their manufacturing process, a complementary operation for obtaining accurate longitudinal and transverse dimensions before their commercialization. For this purpose, the plate contours must be sawn. In most cases this sizing operation must be carried out very accurately, notably when the plates are intended for use in the manufacture of printed circuits.
Various means have already been proposed for sizing plates of this type.
2. The Prior Art
A known arrangement for sizing plates comprises two sawing machines, i.e. one machine for cutting the plate longitudinally in order to obtain the requisite width, and another machine for cutting the plate transversely in order to obtain the proper plate length. Disposed between these two sawing machines is a transfer table adapted to move the plate in a direction across the preceding one. After positioning the plates on a feed table, the plates are presented with one of their longitudinal edges facing the saw blade of the first machine. After the cutting step, the plates are shifted to present their other longitudinal edge in front of the same machine for cutting the plates to the desired width. Then, the plates are moved to a transfer table which causes the plates to present their transverse edges in succession to the saw blade of the second machine. After obtaining the desired length, the plates are removed from the machine assembly. The major inconvenience characterizing this system lies in its complexity. In fact, the machines are loaded and unloaded at two different places, thus requiring several operators for handling the plates.
Another known device comprises a single sawing machine permitting of sawing the plates from beneath. Firstly, the two longitudinal edges are cut to obtain the predetermined plate width, whereafter the plate is rotated manually through one-fourth of a revolution for cutting the two transverse edges to obtain the desired plate length. The chief inconvenience of this system is that the plates must be handled manually.
Another known arrangement comprises a gantry-type machine adapted to saw the plates from above. Various gantry-sawing machines are available which comprise either a cross-motion swivel-head movable beam or a pair of parallel moving beams, or alternately two twin-beams transfer machines with one beam for cutting the plates longitudinally and another beam for cutting the plates transversely. Since the plate surface area is variable, the position of the cutting line is not always the same and varies as a function of the magnitude of said area. Thus, it is difficult in a gantry machine of this type to provide means for automatically removing scraps. Therefore, scraps must be removed manually.